CANCER of the GASTROINTESTINAL TRACT

For the last three decades, cancer of the stomach has been decreasing in frequency in the United States. It remains high in Japan and certain other Oriental nations, and is probably related to the intake of certain foods, some highly seasoned, and others extremely hot. The second most common type of cancer in our country is cancer of the colon and rectum. This often produces a change in bowel habits, the stools becoming more constipated or of small caliber. Bleeding from the rectum is occasionally seen. This is usually red when the tumor growth is low in the colon and darker, brown to black (called melena) when the lesion is high in the colon or coming from the small intestine or stomach. This color change is due to the partial digestion of blood products by bacteria and enzymes in the bowel.
The rectal examination is helpful in detection of many cancers in their early stages. A ten-inch tube with attached light, called a sigmoidoscope can be used to look into the lower bowel, where nearly three-fourths of the cancers are seen. This should be done in conjunction with a complete annual exam for individuals over the age of 40. A new technology in fiber optic viewing, called endoscopy, has developed instruments that can examine the stomach and duodenum (gastroscopy), and the entire colon (colonoscopy).
These procedures are often done on an outpatient basis, and provide even more adequate confirmation than the traditional barium x-rays. The cause of these colon cancers is still somewhat uncertain. It is felt that a high fiber diet, which increases the rapidity of transit through the bowel, will decrease the incidence of cancer. This is probably because the waste products contain many toxins. In contact with the mucous lining of the bowel these can cause irritation and eventual malignant change in the cells. A number of foods, most notably meat, contains toxins (carcinogens) that can be directly associated with cancer. The benz-0-pyrene in a charcoal-broiled steak may be equivalent to that found in about 600 cigarettes. Methylcholanthrene is also a dangerous substance found in many types of meat. Recently discovered is the chemical malonaldehyde, which seems to be increased when the meat is cooked! Certain vegetables are not exempt from association with cancer. Moldy corn, peanuts, soybeans, and other seeds contain a factor called aflatoxin, which has been associated with liver cancer in several countries. It is interesting to note that the incidence of cancer is increasing in many fish that inhabit polluted streams and rivers. Problems with meat inspection also contribute to risk of cancer, in that certain portions of an animal carcass may be preserved for food, while another part of the animal may have actual malignancy.
All of these danger signals are turning more food buyers to a vegetarian diet. In fact the numbers are growing rapidly in the United Kingdom, where a disease called bovine spongiform encephalopathy was discovered in 1985. It will undoubtedly spread to other nations. Often called the “mad cow disease,” this condition results from using animal products such as a bone meal in cattle feed. The cows after a few years go crazy, and become violent. A virus-like particle called a PRION is found in the animal’s brain. Currently it is resistant to most germ killing procedures, including boiling, radiation, and disinfectants. Modern cancer virus research points out the “ounce of prevention” at your supermarket being worth much more than “pounds of cure” in the hospital. Another bit of good news in the treatment of cancer of the colon is that some types can be removed without radical resection of the organ. Many snares, cauteries, and forceps have been devised to remove these cancers from the rectum through the sigmoidoscope. Sometimes when the malignancy is present only as a growth on a stalk, the area involved can be followed with periodic examinations. Other times the removal of a portion of the colon is necessary to effect the cure. The possibility of metastasis to the lymph nodes or liver makes it important to achieve early diagnosis and therapy, if life is to be maximally prolonged.